The Gitzo GS5370B Series 3-5 Aluminum Quick-Release Plate Square B is a 2.2" square plate that features both the 1/4"-20 and the 3/8" camera screws. It is a "B" type plate, and is compatible with G1376M, GH3750QR, and G1576M Off-Center Ballheads, as well as the G1387B & G1385B quick release adapters.